METHOD OF PREPARING PROPYLENE OXIDE OR EPICHLOROHYDRIN

摘要

The invention provides a process for epoxidation of an alkene by reaction with a peracid, characterized by supplying an aqueous phase comprising sulphuric acid, hydrogen peroxide and water and an organic phase comprising acetic acid or propionic acid in a chlorinated hydrocarbon solvent to a liquid-liquid extraction device in such manner that these two phases pass in countercurrent through the extraction device; withdrawing from such extraction device an organic solution of peracid and carboxylic acid in the chlorinated hydrocarbon; passing said organic solution and the alkene cocurrently to a reactor; withdrawing from the reactor a product mixture and effecting fractional distillation thereof; withdrawing from such fractional distillation a product phase comprising the oxirane and a recycle phase comprising carboxylic acid in the chlorinated hydrocarbon, and passing such recycle phase from the distillation to the extraction device to form the organic phase therein. The importance of the invention resides in the integration of the epoxidation step with that of the manufacture of the peracid, and in the fact that the carboxylic acid, sulphuric acid and chlorinated hydrocarbon solvent are all recycled.